1. Technical Field
The present disclosure relates to an access port which is adapted to allow the introduction of surgical instrumentation into a patient's body.
2. Description of the Related Art
In laparoscopic procedures, surgery is performed in the interior of the abdomen through a small incision; in endoscopic procedures, surgery is performed in any hollow viscus of the body through a narrow tube or cannula inserted through a small entrance incision in the skin. Laparoscopic and endoscopic procedures generally require that any instrumentation inserted into the body be sealed, i.e. provisions must be made to ensure that gases do not enter or exit the body through the incision as, for example, in surgical procedures in which the surgical region is insufflated. Moreover, laparoscopic and endoscopic procedures often require the surgeon to act on organs, tissue, and vessels far removed from the incision, thereby requiring that any instruments used in such procedures be relatively long and narrow.
For such procedures, the introduction of a tube into certain anatomical cavities such as the abdominal cavity is usually accomplished by use of a trocar assembly including a cannula assembly and an obturator assembly. Since the cannula assembly provides a direct passage for surgical instrumentation from outside the patient's body to access internal organs and tissue, it is important that the cannula assembly maintain a relatively gas-tight interface between the abdominal cavity and the outside atmosphere. The cannula assembly generally includes a cannula attached to a cannula housing containing a seal assembly adapted to maintain a seal across the opening of the cannula housing.
Since surgical procedures in the abdominal cavity of the body require insufflating gases to raise the cavity wall away from vital organs, the procedure is usually initiated by use of a Verres needle through which a gas such as CO2 is introduced into the body cavity, thereby creating a pneumoperitoneum. The gas provides a positive pressure which raises the inner body wall away from internal organs, thereby providing the surgeon with a region within which to operate and avoiding unnecessary contact with the organs by the instruments inserted through the cannula assembly. An obturator of the obturator assembly is inserted into the cannula assembly and used to puncture the abdominal wall. Following removal of the obturator assembly from the cannula assembly, laparoscopic or endoscopic surgical instruments may be inserted through the cannula assembly to perform surgery within the abdominal cavity.
Generally in the context of insufflatory surgical procedures, there are two sealing requirements for cannula assemblies. The first requirement is to provide a substantially fluid-tight seal when an instrument is not being introduced into or is not already present in the cannula. The second requirement is to provide a substantially fluid-tight seal when an instrument is being introduced into or is already present in the cannula. Additionally, as endoscopic and laparoscopic surgical procedures and techniques have advanced, it has become desirable to accommodate surgical instrumentation of varying outside diameters through a single cannula assembly in a given surgical procedure, thereby minimizing the number of cannula required and facilitating efficiency in the surgical procedure.